Barrier localization effects in AlxGa1-xAs-AlyGa1-yAs superlattices.

We demonstrate that the recently observed phenomenon of barrier localization in magnetic II-VI superlattices is also present in III-V superlattices. We investigate the role of subsidiary minimaand show that above-barrier localization in both the Γ and X barriers occurs for type-I and type-II (001) superlattices in the Al x Ga 1-x As-Al y Ga 1-y As system. In addition, explicit evalulation of the oscillator strengts shows that the interband transitions involving the X-like conduction-band above-barrier states remain even even though these are spatialy direct